Discrimination Method of Gas Pressure Measurement in Coal Seams: Physical Experiment and Model Development

Coal seam gas pressure is a key parameter of gas accident control and gas drainage. At present, there are some problems in field pressure measurement, such as long period, and there is often a need to drill more holes to ensure the reliability of pressure measurement. In this research, a physical gas pressure measurement experiment in a coal sample borehole was carried out, and a mathematical model of gas pressure evolution with time was constructed. Based on the OpenFOAM platform and C++ language, a numerical solver was developed, and the mathematical model was verified by the data of gas pressure in coal seam boreholes. The results show that the evolution process of gas pressure in coal seam boreholes can be divided into two stages. In the first stage, the gas pressure increases rapidly, and the pressure change rate decreases continuously. In the second stage, the gas pressure is slow and stable, and the pressure change rate tends to 0. The correlation coefficients between the mathematical model and the field-measured data are more than 0.94, and the calculation and prediction accuracy are high. Therefore, the model can be used to verify the field data during pressure measurement, which has better field significance and application value.